The objective is the immobilization of hepatocytes for use in an artificial liver device. Hepatocytes will be isolated by established techniques using collagenase digestion and immobilized in a sodium alginate gel matrix. This alginate gel will provide mechanical protection of the immobilized cells. The principles and technology developed in this work will provide a rational basis for design of treatment modalities for acute and chronic liver failure. The viability and function of the hepatocytes will be examined in the short and long term. The viability will be assessed using vital dye assays with both trypan blue and fluorescence dyes. The function of the hepatocytes will be assessed by measuring the reaction kinetics for the mixed function oxidase system (cytochrome P450), the urea cycle, and conjugating enzymes (UDP-glucuronyltransferase and sulfate transferase). In acute liver failure animal models, the immobilized cells will be used both as an intraperitoneal transplant and in an extracorporeal circuit to provide short term liver support. In the last 9 years, the applicant has completed the 5 year General Surgery residency training program at the Massachusetts General Hospital and also received a masters and a doctoral degree in Chemical Engineering at the Massachusetts Institute of Technology. He will apply the education in engineering and his clinical training in Surgery to the development of techniques for artificial liver support. Though the applicant has a background in research, this research was in engineering and not in biochemistry, cell biology, and physiology of digestive diseases. The applicant will require further training and development in learning these basic science skills to become an independent investigator in liver research. The sponsor of the applicant will be Dr. Kurt Isselbacher from the Medical Service of the Massachusetts General Hospital. Dr. Isselbacher will provide the environment necessary to develop basic science skills in liver biochemistry. The Surgical Service of the Massachusetts General Hospital and the Department of Surgery, Harvard Medical School, will provide the academic commitment and laboratory space. Dr. Paul Russell from the Surgical Service of the Massachusetts General Hospital will collaborate on transplant and immunological aspects of the project.